1. Field of the Invention
The present invention relates to the control of an electrically driven vehicle such as, for example, an automotive vehicle of a kind having left and right, independent drive motors.
2. Description of Related Art
The electric motorcar now attracting public attentions is considered a high performance vehicle as it makes use of left and right electric motors such as, for example, in-wheel motors that can be controlled independently from each other. In most of the electric motorcars currently available in the market, the electric motors employed are driven according to either a torque control scheme, that is, a scheme in which the electric current to be supplied to each of the electric motors is controlled, or of a scheme in which the number of revolutions of each of the electric motors is controlled. In those known control schemes, the drive wheels themselves tend to generate a turning force or a slewing force in the event that because of, for example, a change in tire pneumatic pressure, the effective radius differs between those drive wheels. The patent document 1 listed below addresses correction of a difference in driving force brought about by the difference in tire diameters and discloses a control method utilizing threshold values to refrain from exceeding the limit. In this control method, the difference in driving forces is to a certain extent permissible.
[Patent Document 1] JP Laid-open Patent Publication No. 2006-240402